SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1273bf414873a9995534cfa515b729cace4892584e21f554861b5a49b674007a' 
  AND token = 'kkyRvOftZR6pCHQ61JcAICDC+ZkWMI2MrV8z7vzmyk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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