SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4fd14a2032033543abfbb52c979f5e317838cc8dc4624d6d883450cd5291dea7' 
  AND token = 'BP/UXLx2DvvJXrwsW9ivZkAcd2+Z0nTI9QEzlHoBp4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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