SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '853f792820654adf2d05466c1870bd667a4e983993c6d61225f1c29cd7844a65' 
  AND token = 'baKxMMV7Leef3PJFXcjjNbrS1GdLFNGCVcFKWNmGRTE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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