SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '76c7f56392e2ef341e567b3e73324c1d079783d8eba99ee4a239b146a7c8934e' 
  AND token = '1CCS0bpb0RaV2JBypC56sfBMoLfyR6HAk237mCYtReQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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