SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b5282f24289110b53f934a69eaf11185e3528db82a20691b281768fbcdc741f' 
  AND token = '8lUcFzWXywgmoVXm7R+t81pBiFb5GMqvyq3yPD3ChBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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