SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b17d20852d2d3c93206b966b4a5cf42f00231a8704b19b4675a2fe860934bc27' 
  AND token = '4ljFBAl76SHQQEHVWQ4f4RHAuFMDMwiYxlXNAIaPfGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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