SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '693d003aefeaa483a1a2dd48d8affd4d97cc5ac09f937ff60e31e2f0853b7d27' 
  AND token = 'Iwql2SLiWZrw4mMkSJ+zDijMg4fYutmtq1OcDhvMRRA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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