SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5df68f409a063e0cc480fb14cd821bd00a10d3d78b28941bc68e00666af3aece' 
  AND token = 'hcQX4rU2sHyAxwzSN9dziIMIZLQ5qM/wHZeZXA3f21s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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