SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '362ccc8f3680dbce6cf808f0132d28c8dfaf3be461c48ddc36d7604a1456511c' 
  AND token = 'sOYH0vcXtpyjQ2qLfbrP/XOoW9ekSaBaZ1Pxe/Za39k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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