SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5040e5b326f5b05af193edd2529e2c0c45348886604096f2ad5081a78e35cb78' 
  AND token = '2uChhi0mkqX4a4CUng2x/AYsnSwPxPD8N4EiFYtjxKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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