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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18f8ade9b6ca52fa74029d7be502588cf1f1d19d1121406b8fa1b2b4dc9f4dcf' 
  AND token = 'il0rcQIRpIP/uT99sGK5amCwpMzRDq9B5gUs8a+P88A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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