SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bea43ad86d17ca86ed50810c2fd0874bf5a0f7159f4018f9dd45db009a5242be' 
  AND token = 'k94LxHkwTsCjHgHVsPg6nGxWCVQysqN2EaLQb8HKY4k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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