SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0eeed850a70f24b1015f856d7379d98449b5dcac933c9cb29bcfb38955c2790' 
  AND token = '4HnbXm/eb7048wH7d9+nTKsbiCH9RBTnKpOuR23O6rs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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