SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ff502dae082015701969c83f5a62c897de7cd6c12173170bd93078b11203c66' 
  AND token = 'X+osWgfYVKqFlVAzSop3wHKg/626Cu9OG9MK0aqhHHQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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