SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42a5cd4aa9a895ab40375930745a6e8dff170b14f95df726d4bf9dff3726445c' 
  AND token = 'Ma4ixBvfusql4+DmvI9stF1i8SoUZbCrLVvRMSWYn/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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