SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3a75be74d5d07ec032aab3359bfea409d21dce9d2992ff4698806e714cecd7b6' 
  AND token = 'qweKrjpJRP7f1QIU9pNxZduQVw8QFRAaG7q2bVhad+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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