SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '320347c3abadbcdbaa565150da09acc650e65d8fc2075db51b5dbef061fabf55' 
  AND token = 'ofMwUzIuSxfSBXFoT8wuNWAI7u16smFCP5cdbYIDagA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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