SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a934881af29ba7be4a1f494ebb78f15b2138e71c27f9626b7ddcc65a90e662b0' 
  AND token = 'j4vB+W4S9k9qBmxAGb4zD4Kjc+F8GXuUCY2mOkuXOdE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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