SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d886b9622bf8806b7cd51988ee1f534dd1e25bfbcd9ea7e6304f3ca0bd2adbc' 
  AND token = '6BpPZhH57sGsGXXJt2t4tKW6UAH02vyJc9uweL/aLtA=' 
  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"
    }
  }
}