SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c89106ffe4615bdfa3df6d15ad2c2fe1ebe3a8304d975d68e96f7c5dc96e0b2' 
  AND token = 'sGuAO2LoyzVWYGDpwKSxgT9JDqjZCaUsOeaTg912+hk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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