SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b4b9a50ed93af7fc687713279f2dca95d73c1015d4d80bcb53a74c8969906fce' 
  AND token = 'LkzhQtUv/N3FmX7ihmO0xVJv5zWkoc7dXcB65GKJvSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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