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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '528b71e39ca0336e2aa849fc7dd3a7ef0b6ee6469a682d2795d5f0b3aa36d2ba' 
  AND token = 'eKynSIT3j8TvWDVXaRER7xE76oB4LtNmNLgwiv6bdBU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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