SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1fe6888e4c242340d3ead7671173c52d693c442e8e5d2efc1433203c3574539' 
  AND token = 'qEo/LnnfjZqHl0HslsjJKze9/hnCx741NiMVv0bpbHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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