SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'caad8cc7ff6135ed02e50c84534764b515b758c77cc328c30043d81d09be0cfd' 
  AND token = 'LssMHHY/8ymHsNUihqnkIrXKFYPw9kimBkS/RchAGWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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