SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a20202eeea5175ed1cda9e02173de510c4efdec2573349cb406261ec70d05b42' 
  AND token = 'F0fnzjyLFR7wDn8foUcAVN7c+ffuJWwKx8ymKTgXeuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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