SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b771a667e7b57531f7786869e9e489daa124658f5a129502a69284a0a8cafd8' 
  AND token = 'AZaTxtdaUUeAgO83hHKdZ1W7rO6/Xp+BfmDXgW4jKD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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