SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ec84a9382c85b70c59ec7ced6762aa5321f9007f8207750940a814da8084121' 
  AND token = 'a+e8AGIiPcdkI1CvhfgerxmnqIIxaLU35HVF03XGvRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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