SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27a513cb989816367d1ae9593dc4f38c17dbe0eb496a0cd8c07ff5e85333854a' 
  AND token = 'JKcbHKlBH9AmY75vsDldURpDYGIDaboPw1WZnjxrXYM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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