SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbbe70e2b544478402497ad46c7a1d0a0f689fbd29d0022d76ad04dbf2494b12' 
  AND token = 'K8kO+1jEeK/FRxA9l/tlKZz6rJGfHljCZPq29CKqasM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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