SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5dfbb4219f183e3b5624dfe00f1e2a2a4124d1f8bc38e0d85667805ebaebe3ef' 
  AND token = 'FKP2j8CKsK7XiSKUxkruAg6WyETvL92cILe8xzsbkAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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