SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e120b6e09c4893f0f3d3e5068d164bb11251f0c3bf73f438db25bbc8170cdea1' 
  AND token = '6gktcOUO+LGaiZSZjWAzuj8wG8jTP3fbLuTeGVUBXv8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}