SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b24b2a30fade38c7f4f82e0828519d47686bd102d1cad62b8edfea268e445d45' 
  AND token = '389GA99ezPX7MxiwMxWoGao7BKEfunZ1hf8DBdSpFg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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