SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '83492d3d5f6e42f3637dba981d95a7f35aab7c94b60ce7233630c9647c718b44' 
  AND token = 'hF7beIuL3tcP+c/iHdOnSPTSGgOiwk2/y17vlCKiFDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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