SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '364b6fb57d83e9d85027b77f33211a6fe5ed73f0b7f0879f373260685126f9a7' 
  AND token = 'B/qxd/bXalnIzacmowZKpB7MzQCAQuyOpitIPhuJqco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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