SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e6d9a4f94bff6da2c436135321fd158ceb2022d407261d02209ed62484733343' 
  AND token = 'DWoYIWk7hqCs9kscTu2cXkqunn1JBLnZBlH1EV5SDKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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