SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e795f431e1589705ad99eb227e256de1963a063d5c75963f77fcabb3c72fbcf0' 
  AND token = 't5I0KJ/Ix2KpjVGhLZ7Ydh8OyeKHak1mvuJE68PWYuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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