SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '780672dcc533ec0be5d133ffd38289dc8e0d1c6d66e4e6099298b3c317d45c66' 
  AND token = 'nKuwRUf3yuDIK2DbkcRxuQXsMDNY8bzLnh5VY7f2P5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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