SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d619a962e283f7cdb6be229c16fde20fc0831e1bed92b16e09ddb7ec5b943f3' 
  AND token = '+CWVXnfvl2Ua0Wp2+bVR4irWfNgRi85xKavJkvwYIu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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