SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b6f89c61c4798428f47889eb2c78ee0c3e2a5169189d0f1ba12a24aa733b6267' 
  AND token = '1hXIqcKTmeJY4whgOiWGtPFT0A4bnEISvMuLeIlQQKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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