SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bc318a0d8e8db4ffebdf393e2015344399c07742aad96f4ba1f3e56cd82a35c' 
  AND token = 'GoU2zfkOYCk9DD39OJVeXNfGeh1TDnxINxIdKexdgVE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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