SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14763c0597786f367b805342c7cb78c39167f9e3f7d94b6fb1aba08b815af4b8' 
  AND token = 'WGJdDvakZHBDwrEKZ6DydnuD4ngmexUrY4XG+O26Snw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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