SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84507a284cf91595631c36f54de0c1f3abfb1b73465cb5d30b30efc4fcd8fe29' 
  AND token = 'qI/G5nNVPF3CtRfnMGGbPvixnOHFYFG8cYhnRBhmaFM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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