SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '977518746e1c266923e7701f4c3b9b8b894bc52e0c84aebaef5384a7fc3d83fc' 
  AND token = 'RGVS+VIyLfiBYhIIrqMOdTNN04GvmuGVzXMxzUnskes=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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