SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2789b9588db4096e26fa4adc7ffabad0fb808fad98c094e7a6479baea7617168' 
  AND token = 'wut+dmsKKgxFc3YVRvQmgvEfTEAuaq8i9OBukGplW5M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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