SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b625e4dfdafc78c85eda9fda2d6f6d6732938fca191dd9cbe47b96c6f3bea111' 
  AND token = '2FL4SnkqbQD07+TiZE0cvslZl12OvjWURP0g+TiMHE8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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