SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a3974f31fd9047db5052418c53b3215dd120867289bdfe66a873f718ba6b305' 
  AND token = 'Pwoko0rBXbjqUkaGREGrEXyUkgDmotcKOYgm9k9S39Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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