SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2d1c7c0cdd15195cb9ca5c10c51f78cfe95c4f5175286f60a24e2bf46889ba9' 
  AND token = 'gt1vqcYsHDYM4Dqy5yVgSxGyN/IDJ0qJzPC44PCleF8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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