SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4b6aa23dc9b3e2c54c1bcb680af45ffd60f0f3ee887fca4936693dec19528c92' 
  AND token = 'lx24TIBIj7oZgfDUMiv1ohLFBk5/d2xFnYjNuebjugc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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