SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1201b94b1e4044777528b882fd609a9c571e1a0eee5eb23680f0c2932cf1c6d7' 
  AND token = '5jpR8nS53p9e4R1Vdl4PONg4VV+xwzlNW+UaI6P3guI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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