SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4d87228d902e2b4a1db283ed60c1906de255a2cd6bdbe7621cccb5b5e191706' 
  AND token = 'nIDvEkx9IfjskYp8qvlOpPXphjvOHHv9qPGGke2Ol1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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