SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99a4d45be9e64b38cf42ff1d8fe28f73e0ea97335f945247cb2d29551767f6cd' 
  AND token = 'Z6AaMvnl1m2nppCy3nlEmEGhB//NCVqcdrKJXlYmpVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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