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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cda8db02e4ebc0e7e15a1dcde4b97e91e5f1d80d069f6d6e3a7d2fe770666251' 
  AND token = 'K21mIyE7S2FvEcRBmyREHSY/FDiaxQarXKa7MDetUyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}