SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cca53578057b48d93e7865a3b285344c20d846cff262927a49d258a2b1c35f02' 
  AND token = '8wGVoj+I8mznoYO9fvuzLA9LJhdD57rEAdMlx5Il3Ao=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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