SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c4337a7934434e38cf2473626f3ddf8894d5cefdc56825c14afdd841b05a66e4' 
  AND token = 'V/zrLhEpswAmsLDyRHCqydte0BmYYBPIhcWzjLXld4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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