SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8756392241573e988bb75e1d7a88f1b615b2690b2d18d983d1d242245f8422b0' 
  AND token = 'SbIN6VEnIeWG3vhHptoX8XeXKg65IuMfdhD1HZ03ejM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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