SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c38604110b8b6631ab9a25d0c921e5463318bde047f72f6683aadff1e45ac42e' 
  AND token = 'dOLDmnLAOpYrqBLIIT5AUduU7etHQ/WW6ree7Zb5XQg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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