SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb593425ceef716bfcf492034d74244050b0efcf92ffe09445fadcb7373e39fa' 
  AND token = '9TaHn35HM3Omanm/SdufrUlmdraCDbX66Bk6Lcq9y6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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