SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1490a270bd6cf660a81d9573a7f6485e78f2727d52a7cccc42f834f343d277d1' 
  AND token = 'PxdHGwlwifGYIzAcUI/y8RiD99CPpgAUohBdwMN5SzQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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