SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8016bd659fa09e210647432b8cbb49220c472370a1c7f7cb573aee40204b404b' 
  AND token = 'UllDhSU8GKxkJAibB53tqHSNOMh/kxHRWkakdobnwSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00111

JSON explain

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