SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b14ee92f23d29385ddc596c159773647cb03a22e873f0f7bff50fd960823ed1' 
  AND token = 'LIMH4JpYMMJWIF+gYc+cEG+sM+RIte45qOqFsVUZK6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}