SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b3ca74a2ce3093917341bc4f37577ce7e768da3108210d6f41b1138957b3c519' 
  AND token = 'T9N03AohUe/u61FHfcE0pK/rxNHuwQgFJnR0cyEG/UE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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