SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '789a7a17ce9cb0e78cce74193746373bf588c50e7d8f104c4d302aded01a1aaa' 
  AND token = 'SkaS1Itn4feYnYjtkYsYMYrm9W4EZI+o4pR+GlWm6es=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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