SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94d561ba42906f0899b125d5f5f8b9e45857e459fc985b7f9983c5d6ef5deacc' 
  AND token = 'kU3HoOjuTJa5bhlNa+Ue5HaXmvs/fQoZqRqxHcisiZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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