SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16f6b9d6249d46bf2173b60596de600c938ec1ce3ab9a38aa260d9426d91d57a' 
  AND token = 'awG2LBzNiKjYDDFpxhUd8hWwfkNxFVQb0FJJRIU7fhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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