SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6977c2ff18a4d6666d4f05b0fbda9b016759e39f69425fc60d4ae3ed3167d4ad' 
  AND token = 'SBnYmTFZq8Oi63WSnnHVvDfL0iV6iyWmaEOKkgDht4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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