SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4144d615832662f531d7813e6eb982f1cf05d73359006f741b3b5f5564a27322' 
  AND token = 'DIX+B0m2h6N8Y3Qz/u0+6GC7bqmsDpVurdnZmS/sMgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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