SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8de7b6276c2b3b993657748069c75f59453a4b597440f34ba0ac7aab77521ac5' 
  AND token = 'T/XvHNrhFEoBVbKzqBk7vsOVez2bt0Pg8wyZpb7CFts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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