SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f99583913aff3826a91eb4506438de534ed2ac3756b59be82248067d64e51fc' 
  AND token = 'h+Ehv7XqRznpRAN2mtHFGgH84Tl59xnGKKohijj6hqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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