SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a6a854544994613b07ed9ba207f6f98b136a63c77f4a0d0edc6f512ebd485ef' 
  AND token = '0pcnjSsZ0G7XYLiv2gl6Iz0CiowYcRQFoBGRi6fJIPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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