SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c0cec43cf19b6fa9e19cebdedb9ba238816865abd82527a33140b1172c82e5b' 
  AND token = 'sL/WP66UQ/JbXpPS3IjViJezd3AiVP/AI5fUCebwOIg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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