SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a4c6bad55999edb41fb8e4b94dd35230a624228272b16484dd4cbd7708a7542' 
  AND token = 'R4hK3E/0BNro4TZ0hr3sA6Kx3s7giL+/IxOvbN05d/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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