SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d0fe8c148b178a9fd735b8296afd396236b84bc28934bbe3754f1b3381a8317' 
  AND token = '6jvVZxZbGAyjUVpqJairLcYCB/nBGNJkGxKFpn/gwtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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