SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7875559548fc2b2b1a73ee82395578f6313c86496321d4f291ea32e43a041a5' 
  AND token = 'B2/xLQksTJpN/FbW85T1YiFkjgbPUM3CZ99tEdYUrJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}