SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eaeba36dc6a9e802095bf5e426ffa8664e8eb82960662691dd172ee7cab8ab9f' 
  AND token = 'nWtZwnJ7EJYVYGO64uR23t3sNG1Iv8CGjZ2sW8yi/dQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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