SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37f34cb98d1941c4dd262f1060f2f0565bdf95d35946b6cf25413fa9045250a1' 
  AND token = '7a1ZRLKm1SsAapBuxuKhNm7RKNOqa+ls+6EKNb1XFWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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