SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '923deab5e61e49b2f67f1ba6f8d2338a0636dbaf69a9f2875adc962d383e99c5' 
  AND token = 'rvJz3y3D5MhmRHsabLYjUIWXPbJIm8BwGrYGNL7aqy8=' 
  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"
    }
  }
}