SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '358ffffbc1119502b2bdf9b9949571630f4eac0e350a3bce7f30a65390ee084e' 
  AND token = 'g3noepp447gDedRDpeLSsfsNgph8ejL763TX8eypeIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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