SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb8224af1ad207336238a4238eb7e2eb5c09f95c3fa532fef4645efa85302083' 
  AND token = 'JadQ2VILrgjH6SijZDYr96IL+uuhh63lCgBYcJKq+aQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}